Field of the Invention
Exemplary embodiments of the invention relate to a display device in which a light source is normally driven even when a level of a dimming signal is very low.
Description of the Related Art
A liquid crystal display (LCD) utilizes a liquid crystal that is a non-emitting element, and thus requires a backlight unit that produces light.
The backlight unit includes a plurality of light source arrays including a number of light emitting diodes.
The backlight unit is controlled by a dimming method for improvement in image quality.
The dimming method is broadly categorized into an analog dimming method and a digital dimming method. The analog dimming method controls light intensity by linearly adjusting a light driving current supplied to a light emitting diode. The digital dimming method controls light intensity by adjusting a light driving current by a duty ratio of a digital pulse signal.
A display device with a backlight unit of the analog dimming method adjusts a dimming signal according to luminance of an image so as to control brightness of the backlight unit. For instance, the display device increases a level of the dimming signal when an image having a high luminance is displayed, and on the other hand it decreases a level of the dimming signal when an image with a low luminance is displayed.
When an image with a very low luminance is displayed, the level of the dimming signal needs to be considerably lowered, and then it causes the following problems.
Where the dimming signal has a very low level, an integrated circuit that processes the dimming signal fails to recognize (or detect) the dimming signal, and a light emitting diode fails to be turned on or a flicker of the light emitting diode occurs.
Accordingly, a display device using the conventional analog dimming method has a disadvantage that cannot normally display an image having a very low luminance.
It is to be understood that this background of the technology section is intended to provide useful background for understanding the here disclosed technology and as such, the technology background section may include ideas, concepts or recognitions that were not part of what was known or appreciated by those skilled in the pertinent art prior to corresponding effective filing dates of subject matter disclosed herein.